Receiver, tuner and method of processing a television signal

Abstract

The invention is related to a receiver and a tuner respectively, particularly to a television receiver or tuner which can be integrated in a single circuit device. The invention is also related to a method for processing RF signal.

1 . A receiver, comprising:
 a receiver input configured to receive an RF signal;   a first mixer device coupled to the receiver input and configured to convert the RF signal to a first intermediate signal at a first operating frequency;   a second mixer device coupled to the first mixer and configured to convert the first intermediate signal to a second intermediate signal at a second operating frequency;   wherein at least one of the first mixer device and the second mixer device comprises a harmonic rejection mixer.   
   
   
       2 . The receiver of  claim 1 , further comprising:
 a filter device having a pass-band center frequency at the first operating frequency and coupled with an input thereof to the first mixer device and with an output thereof to the second mixer device.   
   
   
       3 . The receiver of  claim 1 , wherein the first mixer device comprises a harmonic rejection mixer and the second mixer device comprises an image rejection mixer. 
   
   
       4 . The receiver of  claim 1 , wherein the second mixer device comprises an image rejection mixer with harmonic rejection. 
   
   
       5 . The receiver of  claim 1 , further comprising a first signal source configured to provide a first local oscillator signal having a variable frequency, wherein the first signal source is coupled to the first mixer device. 
   
   
       6 . The receiver of  claim 5 , wherein the first signal source is configured to provide three local oscillator signals, wherein a second signal of the three local oscillator signals comprises a phase shift of substantially +45° with respect to a first signal of the three local oscillator signals, and wherein a third signal of the three local oscillator signals comprises a phase shift of substantially −45° with respect to the first signal. 
   
   
       7 . The receiver of  claim 5 , wherein the first mixer device is configured to subtractively mix the RF signal with the variable first local oscillator signal to generate the first intermediate signal at the first operating frequency. 
   
   
       8 . The receiver of  claim 1 , further comprising a second signal source coupled to the second mixer device, wherein the second signal source is configured to provide a second local oscillator signal at the first operating frequency. 
   
   
       9 . The receiver of  claim 8 , wherein the second signal source is configured to provide three local oscillator signals, wherein a first signal of the three local oscillator signals comprises a phase shift of substantially +45 degree with respect to a second signal of the three local oscillator signals, and wherein a third signal of the three local oscillator signals comprises a phase shift of substantially −45 degree with respect to the second signal. 
   
   
       10 . The receiver of  claim 1 , wherein the second operating frequency is zero frequency. 
   
   
       11 . The receiver of  claim 1 , wherein the second mixer device comprises an IQ-demodulator. 
   
   
       12 . The receiver of  claim 1 , wherein the harmonic rejection mixer device comprises three mixer stages, each coupled to the input of the harmonic rejection mixer and configured to receive a respective local oscillator signal, wherein a first local oscillator signal comprises a phase shift of substantially +45 degree and a second local oscillator signal comprises a phase shift of substantially −45 degree with respect to a third local oscillator signal. 
   
   
       13 . A television tuner, comprising:
 a low noise amplifier configured to amplify a received signal applied to an input terminal;   an up-down frequency converter connected to the low noise amplifier and configured to convert the amplified received signal to a baseband signal, wherein the up-down frequency converter comprises a first mixer stage configured to up-convert the amplified received signal and a second mixer stage to down-convert the up-converted signal, wherein at least one of the first and second mixer stages comprises a harmonic rejection mixer configured to suppress harmonic portions in a local oscillator signal applied thereto.   
   
   
       14 . The television tuner of  claim 13 , wherein at least one of the first and second mixer stages of the up-down frequency converter comprises an image rejection mixer. 
   
   
       15 . The television tuner of  claim 13 , wherein the up-down frequency converter further comprises a bandpass filter arranged between the first mixer stage and the second mixer stage, wherein the bandpass filter comprises a pass-band in the frequency range of the up-converted signal. 
   
   
       16 . The television tuner of  claim 13 , further comprising:
 a first signal source configured to provide a first local oscillator signal having an adjustable frequency to the first mixer stage; and   a second signal source configured to provide a second local oscillator signal to the second mixer stage.   
   
   
       17 . The television tuner of  claim 13 , further comprising a signal source coupled to the mixer stage that comprises the harmonic rejection mixer, wherein the signal source is configured to provide three local oscillator signals to the harmonic rejection mixer, a first signal of the three local oscillator signals comprising a phase shift of substantially +45° with respect to a second signal of the three local oscillator signals, and a third signal of the three local oscillator signals comprising a phase shift of substantially −45° with respect to the second signal. 
   
   
       18 . The television tuner of  claim 13 , wherein the first mixer stage comprises a harmonic rejection mixer and the second mixer stage comprises and IQ-demodulator, wherein the second mixer stage comprises an IQ-demodulator having a first mixer and a second mixer, each of the first and second mixer comprising an harmonic rejection behavior. 
   
   
       19 . The television tuner of  claim 13 , further comprising:
 a bandpass filter connected downstream of the second mixer stage, wherein the bandpass filter comprises a pass-band center frequency in the range of the signal provided by the second mixer stage.   
   
   
       20 . An integrated tuner configured to receive an RF signal, comprising:
 an input device configured to receive and amplify an RF signal;   a first frequency conversion means coupled to the input device, and configured to convert the amplified RF signal to an intermediate signal at a first intermediate frequency; and   a second frequency conversion means configured to convert the intermediate signal to a baseband signal at a second intermediate frequency;   wherein at least one frequency conversion means of the first and the second frequency conversion means are configured to suppress harmonic portions with respect to a basic frequency in a signal applied thereto.   
   
   
       21 . The integrated tuner of  claim 20 , further comprising:
 filter means arranged between the first frequency conversion means and the second frequency conversion means, wherein the filter means comprises a pass-band center frequency at the first intermediate frequency.   
   
   
       22 . A method of processing a television signal, comprising:
 receiving the television signal;   providing a first local oscillator signal with an adjustable frequency;   up-converting the received television signal to a first intermediate signal at a first intermediate frequency;   filtering the first intermediate signal to suppress undesired signals portions generated during up-conversion;   down-converting the first intermediate signal to a second intermediate signal at a second intermediate frequency; and   suppressing harmonic signal portions during converting to at least one signal of the first and second intermediate signals.   
   
   
       23 . The method of  claim 22 , wherein up-converting the first intermediate signal comprises providing a second local oscillator signal with the first intermediate frequency. 
   
   
       24 . The method of  claim 22 , wherein providing the first local oscillator signal comprises:
 providing a first signal having the adjustable frequency;   providing a second signal having the adjustable frequency and a phase shift of substantially −45° with respect to the first signal; and   providing a third signal having the adjustable frequency and a phase shift of substantially +45° with respect to the first signal.   
   
   
       25 . The method of  claim 24 , wherein suppressing the harmonic signal portions comprises:
 amplifying the at least one signal by a factor of approximately 1.41;   converting the amplified signal with the first signal;   converting the at least one signal with the second signal;   converting the at least one signal with the third signal; and   summing together all the converted signals.